[rescue] [OT] S: IBM /370 or /390 card

[Joshua Boyd]

On 9/12/23 18:08, Lionel Peterson via rescue wrote:
> Emulating a 68000 to emulate a 370?
>
> At some point it starts to resemble the light 'hack' in an early 
> big-bang theory episode:
>
> https://youtu.be/onZ4KMM94yI?si=AZGAKQr5QvL3yZrD
>
> I mean I get it, but...


If we are going to call the XT/370 an emulator, then isn't a Motorola 
68000 chip just also an emulator?  As I understand it, when you get to 
microcoded chips, there is no actual hardware that runs the actual 
binary instruction set sent to the processor. With either the regular 
68k or the 370 implemented in 68k microcode, the CPU reads an 
instruction of the either 68k or 370 origin, then looks that up in ROM 
for how to execute it.

Now, is a gate level re-implementation of a 68k on an FPGA emulation? If 
so, then I suppose that means anything on an FPGA is emulation. Is a 
blackbox external "reimplementation" of a 68k on an FPGA or ASIC 
emulation? The MiSTer people, to my understanding, state that it isn't 
but I feel suspicious about that, and would probably err on calling that 
emulation.  What if it was a blackbox re-implementation but could run 
original microcode? I probably don't want to even debate that one.